Scientists meticulously design their research studies so they can make conclusive statements about what their results mean. However, firm conclusions from a single study are rarely the final goal. It is usually necessary for outcomes to be replicated by other research groups and labs, long before they can be translated to the clinic. In preclinical research, reproducibility depends on tight control of numerous factors. For example, while the health status of the laboratory animal is critical, there are also environmental factors to consider: diet, bedding, light cycles, noise, humidity… The list goes on. All can have undesired effects on research outcomes.
Diet as a source of variation
While it is recognized that diet affects phenotype, the potential for diet to introduce variability is often overlooked. To assist researchers in choosing the best diet for their work, we have created resources to help researchers understand how different diets can have an impact on research outcomes. In addition, our nutritionists are available to answer any questions you may have about your project plans.
As an example of a seemingly small component in diet causing unpredictable outcomes, there is now a wealth of evidence showing that isoflavones – a plant-derived compound with estrogenic activity, and present in variable quantities in rodent diets containing soybean meal – are capable of influencing a very broad range of physiological systems (summarized in the Table below).
There are numerous factors to consider, and each research study will have different needs. Our Teklad Global Rodent diets are designed for life stage and research purpose, with reduced or minimal levels of isoflavones. These fixed formulas are produced utilizing the documented practices illustrated in the graphic below:
Diets for experimental manipulation
Custom diets have been used as a research tool for a long time, but nutritional knowledge has advanced considerably in recent years, offering new opportunities for study design. Some ways diets can be used as research tools are illustrated in the figure below:
It is highly recommended that researchers who are planning to use a custom diet for a new project collaborate with a trusted nutritionist. These professionals can formulate diets with specific additions or deficiencies, including diets designed to mimic human dietary intakes, such as Western or Mediterranean. The sharing of researcher expertise on a specific subject matter coupled with the knowledge of nutrition, ingredients and diet manufacturing can make a custom diet a precision tool for creating experimental conditions that answer complex research questions.
Selecting an appropriate diet
While there are numerous ways a diet can be a research variable, diet is a research tool when it is carefully selected. Choose a diet vendor that prioritizes vendor selection, ingredient choice, has practices in place to carefully manufacture products, and has the in-house expertise to answer your questions.
Investing time in diet choice upfront can make all the difference, resulting in better quality research and improved translatability from animal models to humans. Our nutritionists are available to discuss the impact diet can have on models used in a variety of research areas.